public class Example3_6 {
  public static void main(String arg[]) {
    double sum = 0,item = 1;
    int i = 1,n = 20;
    while(i<n) {
      sum = sum+item;
      i = i+1;
      item = item*(1.0/i);
    }
    System.out.println("sum="+sum);
  }
}
